The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
FIG. 1 illustrates an example of a method for depositing a film on a substrate such as a semiconductor wafer using thermal atomic layer deposition (tALD). At 10, a precursor is introduced into a reaction volume of a processing chamber to expose a substrate such as a semiconductor wafer. At 14, the precursor is purged from the reaction volume. At 16, a reactant gas is introduced into the reaction volume. For example, the reactant gas may be ammonia. At 18, the reactant gas is purged.
A resulting film on the substrate has negligible damage to an extreme low k (ELK) dielectric layer and conformal step coverage. However, the film has poor film density, typically around 8.8 g/cm3. This causes poor barrier performance in Cu thermal diffusion and moisture out-diffusion from the ELK dielectric layer.
In contrast, ion-induced atomic layer deposition (iALD) or plasma-enhanced atomic layer deposition (PEALD) processes use a capacitively-coupled plasma (CCP) treatment with a combination of argon, hydrogen, and ammonia at 16 in FIG. 1. The resulting film has high film density (13 g/cm3) and good step coverage. However, the film has significant ELK damage, yield loss, and high content of undesirable carbon impurity (for example, >20 atomic %).